CVE-2026-77118
CVE-2026-77118 is a Out-of-bounds Write vulnerability. O3 Security confirms whether CVE-2026-77118 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
A heap out-of-bounds write exists in the Photo CD (PCD) decoder of GraphicsMagick. In DecodeImage() (coders/pcd.c), the Huffman delta loop advances its output pointer with q++ after…
Description
A heap out-of-bounds write exists in the Photo CD (PCD) decoder of GraphicsMagick. In DecodeImage() (coders/pcd.c), the Huffman delta loop advances its output pointer with q++ after every decoded delta and never checks it against the end of the heap-allocated luma/chroma plane buffers. The pointer is repositioned only when a sync marker introduces a new plane/row; between sync markers the run length is bounded solely by the input.
A crafted PCD file that positions the pointer near the end of a plane and then supplies a long run of deltas with no intervening sync therefore walks the pointer past the end of the allocation and writes through it. Processing an untrusted PCD file — for example with gm convert or gm identify, or through any application linked against libGraphicsMagick — can corrupt heap memory beyond the buffers.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-77118 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-77118 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-77118. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-77118 in your dependencies?
O3 detects CVE-2026-77118 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.